US5303580A - Method and arrangement for determining the state of deterioration of a catalyzer - Google Patents

Method and arrangement for determining the state of deterioration of a catalyzer Download PDF

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Publication number
US5303580A
US5303580A US07/870,264 US87026492A US5303580A US 5303580 A US5303580 A US 5303580A US 87026492 A US87026492 A US 87026492A US 5303580 A US5303580 A US 5303580A
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Prior art keywords
catalyzer
variable
deterioration
lambda
deterioration variable
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US07/870,264
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English (en)
Inventor
Erich Schneider
Eberhard Schnaibel
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1439—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the position of the sensor
    • F02D41/1441—Plural sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/007—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/02—Catalytic activity of catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the invention relates to a method and an arrangement for determining the performance loss (state of deterioration) of a catalyzer which is mounted in the exhaust gas flow of an internal combustion engine.
  • Forming a relationship between the measuring signal and the test signal permits the influence of various operating conditions on the deterioration variable to be reduced. If a measuring signal having a large amplitude occurs forward of the catalyzer, that is exhaust gas is supplied to the catalyzer having a large deviation from the lambda value one, it is understood that the amplitude of the lambda signal at the output of the catalyzer also increases since, with the same storage capacity of the catalyzer, that much more unconverted toxic gas exits from the catalyzer the greater the amount supplied at the input of the catalyzer.
  • the method of the invention distinguishes from the above-described methods in that, in order to reduce the influence of various operating conditions on the deterioration state variable, actual values of such operating state variables are detected which affect the oxygen storage capacity in the catalyzer and the deterioration variable is corrected based on these values.
  • the arrangement according to the invention includes the above-mentioned probes for detecting the measuring signal and the test signal and a unit for relating these two signals to each other.
  • the arrangement includes a correcting unit for correcting the deterioration variable on the basis of actual values of such operating state variables which affect the oxygen storage operations in the catalyzer.
  • the operating variables which are detected include especially the controller position, the controller frequency and the air-mass flow.
  • the conventionally computed deterioration variable is reduced with increasing enlargement of the deviation of the controller position from the lambda value one and with increasing air-mass flow while the deterioration variable is increased with increasing controller frequency.
  • An especially significant advantage is that the deterioration variable is determined only when the test signals for rich and lean mixture follow each other at the spacing of the controller period. Then it is certain that the catalyzer fluctuates always between a first state wherein the catalyzer is completely filled with oxygen and a second state wherein it is entirely empty of oxygen. In this way, well defined output states for the oxygen storage sequence in the catalyzer are present. This, in turn, leads to especially reliable values for the deterioration variable.
  • FIG. 1 is a schematic of a catalyzer having a lambda probe in the exhaust gas flow forward of the catalyzer and a lambda probe in the exhaust gas flow rearward of the catalyzer;
  • FIGS. 2a to 2e show idealized time-dependent traces of lambda values forward (thin lines) and rearward (thick lines) of a catalyzer;
  • FIG. 3 is a flowchart of a method for correcting the value of the deterioration variable in dependence upon values of operating conditions of the internal combustion engine
  • FIG. 4 shows a method step which can be interposed between the marks A and B in the flowchart of FIG. 3 and in which case, the step s5 in FIG. 3 is deleted;
  • FIG. 5 shows a flowchart step which can be interposed at the position of step s2 between the marks B and C in FIG. 3.
  • FIG. 1 shows a schematic of an internal combustion engine 10, a catalyzer 11, and function groups for evaluating the state of deterioration of the catalyzer, namely, a computation unit 12 and a lambda controller 13.
  • An air-flow sensor 14 is mounted in the intake pipe of the engine 10 and provides a signal which is supplied to the computation unit as well as to the lambda controller.
  • a forward lambda probe 15.v is mounted having a lambda value signal ⁇ -- V which is likewise supplied to the lambda controller and the computation unit 12.
  • a rearward lambda probe 15.h is mounted rearward of the catalyzer and provides a lambda value signal ⁇ -- H which is supplied to the computation unit 12.
  • the computation unit 12 determines the maximum values of the signals ⁇ -- V and ⁇ -- H as measuring signal and test signal, respectively, and computes a preliminary value for the deterioration state AZ of the catalyzer 11 from the relationship of these signals to each other in a conventional manner. In the following, it is assumed that the preliminary value is computed by means of the quotient of the test signal to the measurement signal, that is, ⁇ -- H -- MAX/ ⁇ -- V -- MAX.
  • FIG. 2a shows with a thin line an idealized time-dependent trace of the lambda value ⁇ -- V under the assumption that a two-level control is carried out on the engine with an exclusively integral response with the exhaust gas of the engine being supplied to the catalyzer 11. Furthermore, it is assumed that the time-dependent trace of the signal ⁇ -- V corresponds precisely without distortion to the time-dependent trace of the fuel quantity metered to the engine by the lambda controller. Finally, it is assumed that the control takes place to the lambda value one. This means that the triangular oscillation of the signal ⁇ -- V is symmetrical with reference to the lambda value one.
  • FIG. 2a as well as FIGS. 2b to 2e relate however to a catalyzer which is in a deterioration state in which it is no longer able to store all the oxygen which arrives during the lean phase.
  • oxygen exits at the outlet of the catalyzer and, for this reason, the lambda value ⁇ -- H increases to values greater than one.
  • the catalyzer is filled abruptly with oxygen and then, at its output, essentially the same lambda value is measured as at its input. In practice, the oxygen store does not fill abruptly but instead slowly.
  • T1 defines the time point at which the lambda value ⁇ -- H jumps to the lambda value ⁇ -- V for the reason mentioned above.
  • T0 Up to time point T0, at which the signal ⁇ -- V drops below the value one, the signal traces of ⁇ -- V and ⁇ -- H are coincident.
  • the signal ⁇ -- H is shown with a thick line.
  • the oxygen store is emptied. It is assumed that the oxygen store is abruptly empty at time point T1 whereupon uncombusted exhaust gas components penetrate through the catalyzer 11 to the rearward lambda probe 15.h. This has as a consequence that from time point T1', the time-dependent trace of ⁇ -- H corresponds to that of ⁇ -- V. This applies up to time point T0' at which the lambda value one is exceeded coming from rich values. The storage of oxygen then begins anew.
  • the amplitude of the signal ⁇ -- V is identified by ⁇ -- V -- MAX and the amplitude of the signal ⁇ -- H is identified by ⁇ -- H -- MAX. These values define the measurement signal and the test signal, respectively.
  • the quotient ⁇ -- H -- MAX/ ⁇ -- V -- MAX is the deterioration variable AZ.
  • FIG. 2a as in FIGS. 2b to 2e, the particular area below the signal ⁇ -- V is shown hatched in the time spans in which oxygen is stored in the catalyzer.
  • the termination of the storage operation because of an overflow of the store corresponds to the time point T1 of the change of the lambda value ⁇ -- H.
  • the time point T1 is shifted further forward.
  • FIG. 2b One such case is shown in FIG. 2b.
  • FIGS. 2c to 2e show cases wherein the value of ⁇ -- H -- MAX changes because of special conditions in the operating condition of the engine and not because of a change of the deterioration state of the catalyzer.
  • FIG. 2c shows the case wherein the lambda signal ⁇ -- V -- MAX remains too small during an oscillating period of the lambda controller. It is assumed that it is that signal in the lean region. Then, the catalyzer cannot store as much oxygen as it actually still could store notwithstanding its advanced deterioration. This, in turn, has the consequence that already after a short time in the rich phase, the oxygen stored in the catalyzer is completely consumed so that the signal ⁇ -- H -- MAX is already reached when the signal ⁇ -- V still has a very high value.
  • FIG. 2d relates to the case wherein the control position is shifted toward rich.
  • the lean phase is always shorter than the rich phase.
  • the oxygen stored during the lean phase is already consumed at a considerably earlier time point than it would otherwise have been consumed at the end of the rich phase.
  • a larger value for ⁇ -- H -- MAX then results from the foregoing.
  • FIG. 2e is directed to the case wherein the control frequency is increased.
  • the air-mass flow is unchanged.
  • the phase is shortened in which the oxygen stored during the lean phase is consumed.
  • a shortened time duration lies between the time points T1 and T0 which, in turn, has the consequence that the value of ⁇ -- H jumps to a lower value ⁇ -- H -- MAX.
  • the increase of the control frequency operates less on ⁇ -- H -- MAX as shown above since the increase of the control frequency is caused mostly by an increased air-mass flow.
  • An increased air-mass flow however leads to a shortened attainment of the saturation condition or of the empty state of the catalyzer with reference to oxygen whereby the time span between T1 and T0 is again lengthened.
  • the deterioration variable AZ computed from the ratio ⁇ -- H -- MAX/ ⁇ -- V -- MAX increases with increasing deviation of the control position from the lambda value one and with increasing air-mass flow; however, with an increase of the control frequency, the deterioration variable is reduced. Accordingly, the deterioration variable AZ is in each case corrected in the reverse direction when such changes of control position, of air-mass flow and/or of control frequency are determined. How this correction can take place will now be explained with the aid of FIG. 3.
  • step s1 of the flowchart of FIG. 3 the signals ⁇ -- V, ⁇ -- H, ⁇ , F -- ⁇ and LM are detected.
  • ⁇ is the deviation of the control position from the lambda value one
  • F -- ⁇ is the control frequency
  • LM is the inducted air-mass flow.
  • the measuring signal ⁇ -- V -- MAX and the test signal ⁇ -- H -- MAX are determined for each half period of a controller oscillation.
  • a decision step s2 is reached via two marks A and B wherein a check is made as to whether the test signals for rich and lean lie at the interval of the controller period. If this is the case, the program continues with a step s3 via a mark C.
  • step s3 the preliminary value of the deterioration variable AZ is formed in the conventional manner as a ratio ⁇ -- H -- MAX/ ⁇ -- V -- MAX.
  • step s4 this value is corrected with the aid of the values LM and F -- ⁇ as described in FIG. 3 in step s4.
  • LM -- 0 is a standard air-mass flow and F -- ⁇ -- 0 is a standard controller frequency.
  • step s5 A further correction of AZ takes place on the basis of value ⁇ in step s5 in FIG. 3 in the manner shown.
  • k1 and k2 are constants.
  • the original value of AZ which has been corrected several times in this manner is averaged in step s6 with previously determined corrected values of AZ.
  • step s7 an investigation is made in step s7 as to whether the method should be ended. If this is not the case, then the sequence is repeated starting with step s1.
  • step s7 is also reached starting from step s2 via a mark D when it occurs that the test signals for rich and lean do not lie in essentially the interval of the controller period.
  • step s2 With the aid of step s2, a change of the value of AZ applicable previously should be avoided when the case of FIG. 2c occurs. This can occur especially with a two-point controller having dissimilarly large P-jumps to rich and to lean (larger jumps in the direction of rich).
  • step s5 of the correction of the control position can be deleted and therefor, a step is interposed between the above-mentioned marks A and B as shown in FIG. 4. According to this step, a deviation ⁇ of the control position is eliminated from the lambda value before the actual value of the deterioration variable AZ is determined.
  • step s2 between the marks B, C and D is substituted by the step shown in FIG. 5.
  • an investigation is made as to whether two or more P-jumps of dissimilar magnitude take place sequentially in a short time span. As already explained, this measure acts to eliminate difficulties as they occur in cases shown by means of FIG. 2c.
  • the deterioration variable is corrected in the manner described above, it is possible to determine this variable in a reliable manner during many operating conditions and not only during a few selected operating conditions.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Testing Of Engines (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
US07/870,264 1991-04-17 1992-04-17 Method and arrangement for determining the state of deterioration of a catalyzer Expired - Lifetime US5303580A (en)

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DE4112479 1991-04-17
DE4112479A DE4112479C2 (de) 1991-04-17 1991-04-17 Verfahren und Vorrichtung zum Bestimmen des Alterungszustandes eines Katalysators

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5517848A (en) * 1993-03-16 1996-05-21 Mitsubishi Denki Kabushiki Kaisha Exhaust gas purification system for internal combustion engine, and apparatus and method for controlling the same
US5555868A (en) * 1991-10-23 1996-09-17 Transcom Gas Technologies Pty. Ltd. Gas delivery system
US5684248A (en) * 1995-09-20 1997-11-04 Toyota Jidosha Kabushiki Kaisha Device for determining the degree of deterioration of a catalyst
US5706652A (en) * 1996-04-22 1998-01-13 General Motors Corporation Catalytic converter monitor method and apparatus
US5929320A (en) * 1995-03-16 1999-07-27 Hyundai Motor Company Apparatus and method for judging deterioration of catalysts device and oxygen content sensing device
EP0972927A3 (de) * 1998-07-17 2002-04-03 Denso Corporation Abgasreinigungssystem und- verfahren für eine Brennkraftmaschine
US20020107589A1 (en) * 2000-09-29 2002-08-08 Wolfgang Grimm Method and device for determining changes in technical systems such as electric motors caused by ageing
EP1302648A2 (de) * 1996-06-21 2003-04-16 Ngk Insulators, Ltd. Verfahren zur Steuerung des Abgassystems eines Motors
US20040074227A1 (en) * 1993-04-26 2004-04-22 Hitachi, Ltd. System for diagnosing deterioration of catalyst
US20040255655A1 (en) * 2002-10-19 2004-12-23 Michael-Rainer Busch Device and method for determining the state of ageing of an exhaust-gas catalytic converter
US20060168943A1 (en) * 2005-01-18 2006-08-03 Eberhard Schnaibel Method for operating an internal combustion engine and device for implementing the method
US8065871B1 (en) 2007-01-02 2011-11-29 Cummins Ip, Inc Apparatus, system, and method for real-time diagnosis of a NOx-adsorption catalyst
US8756922B2 (en) 2011-06-10 2014-06-24 Cummins Ip, Inc. NOx adsorber catalyst condition evaluation apparatus and associated methods

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2626433B2 (ja) * 1992-12-09 1997-07-02 トヨタ自動車株式会社 触媒劣化検出装置
KR100474818B1 (ko) * 1997-02-19 2005-05-16 삼성전기주식회사 촉매변환기의열화감지장치
DE19819204C1 (de) 1998-04-29 1999-09-30 Siemens Ag Verfahren zur Abgasreinigung mit Trimmregelung

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US3962866A (en) * 1973-01-31 1976-06-15 Robert Bosch G.M.B.H. Internal combustion exhaust catalytic reactor monitoring system
US4007589A (en) * 1973-01-31 1977-02-15 Robert Bosch G.M.B.H. Internal combustion exhaust catalytic reactor monitoring system
DE3500594A1 (de) * 1985-01-10 1986-07-17 Robert Bosch Gmbh, 7000 Stuttgart Zumesssystem fuer eine brennkraftmaschine zur beeinflussung des betriebsgemisches
US5154055A (en) * 1990-01-22 1992-10-13 Nippondenso Co., Ltd. Apparatus for detecting purification factor of catalyst
US5159810A (en) * 1991-08-26 1992-11-03 Ford Motor Company Catalytic converter monitoring using downstream oxygen sensor

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DE2444334A1 (de) * 1974-09-17 1976-03-25 Bosch Gmbh Robert Verfahren und einrichtung zur ueberwachung der aktivitaet von katalytischen reaktoren
CH668620A5 (de) * 1984-04-12 1989-01-13 Daimler Benz Ag Verfahren zur ueberpruefung und justierung von katalytischen abgasreinigungsanlagen von verbrennungsmotoren.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3962866A (en) * 1973-01-31 1976-06-15 Robert Bosch G.M.B.H. Internal combustion exhaust catalytic reactor monitoring system
US4007589A (en) * 1973-01-31 1977-02-15 Robert Bosch G.M.B.H. Internal combustion exhaust catalytic reactor monitoring system
DE3500594A1 (de) * 1985-01-10 1986-07-17 Robert Bosch Gmbh, 7000 Stuttgart Zumesssystem fuer eine brennkraftmaschine zur beeinflussung des betriebsgemisches
US5154055A (en) * 1990-01-22 1992-10-13 Nippondenso Co., Ltd. Apparatus for detecting purification factor of catalyst
US5159810A (en) * 1991-08-26 1992-11-03 Ford Motor Company Catalytic converter monitoring using downstream oxygen sensor

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5555868A (en) * 1991-10-23 1996-09-17 Transcom Gas Technologies Pty. Ltd. Gas delivery system
US5517848A (en) * 1993-03-16 1996-05-21 Mitsubishi Denki Kabushiki Kaisha Exhaust gas purification system for internal combustion engine, and apparatus and method for controlling the same
US7021044B2 (en) 1993-04-26 2006-04-04 Hitachi, Ltd. System for diagnosing deterioration of catalyst
US7424801B2 (en) 1993-04-26 2008-09-16 Hitachi, Ltd. System for diagnosing deterioration of catalyst
US20040074227A1 (en) * 1993-04-26 2004-04-22 Hitachi, Ltd. System for diagnosing deterioration of catalyst
US20060168946A1 (en) * 1993-04-26 2006-08-03 Hitachi, Ltd. System for diagnosing deterioration of catalyst
US7114326B2 (en) 1993-04-26 2006-10-03 Hitachi, Ltd. System for diagnosing deterioration of catalyst
US5929320A (en) * 1995-03-16 1999-07-27 Hyundai Motor Company Apparatus and method for judging deterioration of catalysts device and oxygen content sensing device
US5684248A (en) * 1995-09-20 1997-11-04 Toyota Jidosha Kabushiki Kaisha Device for determining the degree of deterioration of a catalyst
US5706652A (en) * 1996-04-22 1998-01-13 General Motors Corporation Catalytic converter monitor method and apparatus
EP1302648A2 (de) * 1996-06-21 2003-04-16 Ngk Insulators, Ltd. Verfahren zur Steuerung des Abgassystems eines Motors
EP1302648A3 (de) * 1996-06-21 2005-04-27 Ngk Insulators, Ltd. Verfahren zur Steuerung des Abgassystems eines Motors
EP0972927A3 (de) * 1998-07-17 2002-04-03 Denso Corporation Abgasreinigungssystem und- verfahren für eine Brennkraftmaschine
US20020107589A1 (en) * 2000-09-29 2002-08-08 Wolfgang Grimm Method and device for determining changes in technical systems such as electric motors caused by ageing
US6829515B2 (en) * 2000-09-29 2004-12-07 Robert Bosch Gmbh Method and device for determining changes in technical systems such as electric motors caused by ageing
CN100412563C (zh) * 2000-09-29 2008-08-20 罗伯特-博希股份公司 用于检测技术***由老化引起的改变的方法及装置
US20040255655A1 (en) * 2002-10-19 2004-12-23 Michael-Rainer Busch Device and method for determining the state of ageing of an exhaust-gas catalytic converter
US7021129B2 (en) 2002-10-19 2006-04-04 Daimlerchrysler Ag Device and method for determining the state of aging of an exhaust-gas catalytic converter
US20060168943A1 (en) * 2005-01-18 2006-08-03 Eberhard Schnaibel Method for operating an internal combustion engine and device for implementing the method
US8065871B1 (en) 2007-01-02 2011-11-29 Cummins Ip, Inc Apparatus, system, and method for real-time diagnosis of a NOx-adsorption catalyst
US8756922B2 (en) 2011-06-10 2014-06-24 Cummins Ip, Inc. NOx adsorber catalyst condition evaluation apparatus and associated methods

Also Published As

Publication number Publication date
DE4112479C2 (de) 2002-06-06
ITMI920882A1 (it) 1993-10-10
DE4112479A1 (de) 1992-10-22
JP3313135B2 (ja) 2002-08-12
IT1258314B (it) 1996-02-22
JPH05179934A (ja) 1993-07-20
ITMI920882A0 (it) 1992-04-10

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